The present invention is directed to an improvement in rigid foams.
Rigid polyurethane foams are well known in the art as described in POLYURETHANES: CHEMISTRY AND TECHNOLOGY PART II TECHNOLOGY, by Saunders and Frisch, Interscience Publishers, 1964, Chapter VII, Rigid Foams, pp 193-298 all of which is incorporated herein by reference. Such foams have utility as insulation for tanks, pipes and the like as well as refrigerator and freezer cabinets and the like.
In such applications, the K-factor, dimensional stability and/or expansion at demold are significant properties. The present invention provides a method for improving one or more of these properties.